1. Field of the Invention
The present invention relates to the mold-less forming of patterns in relief on foamed thermoplastic material, and more particularly to the forming of a 3-D relief pattern on foam plastic material by the application of radiant heat energy to the foam plastic material.
2. Description of the Related Art
Common methods of producing large dimensional signs include routing, sandblasting, vacuum-forming, pressure molding, and hot-die forming. These methods have many drawbacks. Vacuum-forming, pressure-molding, and hot-die forming require the construction of dies, which can be costly and time-consuming to produce. Routing and sand-blasting do not require molds or dies, but have their own drawbacks. Routing is labor intensive if manual, and requires specialized tool-path programming if automated. Both sandblasting and routing generate noise and dust. Sandblasting in particular uses silica sands that can pose a serious health hazard, and therefore requires special safety equipment. Methods of forming relief patterns in foam using radiant energy eliminate the problems of sandblasting, routing, or the like, and may be divided into methods based on laser ablation, methods based on differential expansion in foam, and methods based on differential collapse in foam.
It would be desirable, therefore, to have a method forming relief patterns in foam using radiant energy that is capable of producing dimensional signage of at least several feet in length and width, while requiring neither special dies nor expensive specialized equipment, nor producing noise and dust. A method with the qualities described would be likely to have additional applications in other industries involving fabrication of items in relief, such as architectural decor and novelty items.
Thus, a 3-D relief pattern blank and method of using solving the aforementioned problems is desired.